Oscillating apparatus for arc welding equipment

ABSTRACT

For oscillating the welding torch or head, in apparatus for arc welding metal shapes such as large pipes together, variably adjustable eccentric means, are secured under spring pressure to a rotary driver driven by an appropriate motor. A micrometer screw means mounted on the rotary driver has a circumferentially grooved head engaging a flange on the eccentric. As this screw is turned in or out the eccentricity of the variable eccentric is set with accuracy. This micrometer screw is mounted for radial movement on the rotary driver member adjacent and facing the eccentric. The eccentric in turn drives a gyrating member which does not rotate but whose radius of gyration corresponds to the adjusted eccentricity. The gyrating member rocks a follower arm mounted on a rock shaft which shaft also supports the welding head for reciprocating motion. By separate adjusting means, the welding head may be aligned with the weld line independently of its amplitude of reciprocation.

United States Patent Nelson et al.

[ OSCILLATING APPARATUS FOR ARC WELDING EQUIPMENT [75] Inventors: Jerome William Nelson; James Bennett Randolph, both of Houston, Tex.; Robert Earl Pollock, deceased, late of Crownpoint, Ind., by Peggy Pollock, executrix, Crownpoint, Ind.

[73] Assignee: CRC-Crose International, Inc.,

Houston, Tex.

[22] Filed: Dec. 3, 1973 [21] Appl. No.: 421,339

Related U.S. Application Data [63] Continuation-impart of Ser/No. 254,192, May 17,

1972, Pat. No. 3,806,694.

[52] U.S. Cl 219/60 A; 74/117; 219/76; 219/124; 219/125 R [51] Int. Cl... B23K 9/02; B23K 9/30; Fl6l-l 29/04 [58] Field of-Search 74/117; 219/60 A, 76, 124, 219/125 R, 125 PL [56] References Cited UNITED STATES PATENTS 2,932,255 4/1960 Neukirch 74/117 X 3,035,156 5/1962 Staley 219/125 R 3,396,263 8/1968 Even et al. 219/125 R X [451 Sept. 2, 1975 3,681,564 8/1972 Hiyama ct al 219/125 R Primary Examiner-J. V. Truhe Assistant ExaminerN. D. Herkamp Attorney, Agent, or FirmEdwin M. Thomas [5 7 ABSTRACT For oscillating the welding torch or head, in apparatus for arc welding metal shapes such as large pipes together, variably adjustable eccentric means, are secured under spring pressure to a rotary driver driven by an appropriate motor. A micrometer screw means mounted on the rotary driver has a circumferentially grooved head engaging a flange on the eccentric. As this screw is turned in or out the eccentricity of the variable eccentric is set with accuracy. This micrometer screw is mounted for radial movement on the rotary driver member adjacent and facing the eccentric. The eccentric in turn drives a gyrating member which does not rotate but whose radius of gyration corresponds to the adjusted eccentricity. The gyrating member rocks a follower arm mounted on a rock shaft which shaft also supports the welding head for reciprocating motion. By separate adjusting means, the welding head may be aligned with the weld line independently of its amplitude of reciprocation.

7 Claims, 4 Drawing Figures OSCILLATING APPARATUS FOR ARC WELDING EQUIPMENT This application is a continuation in part of Ser. No. 254,192, filed May 17, 1972, now US. Pat. No. 3,806,694.

BACKGROUND AND PRIOR ART As described in the in the above mentioned U.S. Pat. No. 3,806,694, a successful apparatus for electrical arc welding of girth joints in large pipelines, and for making other analogous welds, comprises a welding means mounted on a traveling carriage. A guide track mounted on one of the pipe sections or other work pieces to be joined together supports and guides with accuracy the movement of a self-propelled carriage on which the welding instrumentality is mounted. Customarily, a \/-gap is formed between the two pipe ends or other pieces to be joined together. With thick walled work pieces, several welding passes may be required to complete the welded joint. For proper filling with molten metal, the welding head needs to be oscillated or reciprocated back and forth across the gap and the width of reciprocation varies and changes with different joints and as successive passes are made to fill and cap the weld.

Hence, it is necessary to provide means for changing the width or amplitude of oscillation of the welder nozzle. Previous devices designed for this purpose have been difficult to adjust or have required much time to effect an accurate adjustment. In the parent application there is described an instrument for welding similar joints. It includes an adjusting means wherein a rotarily shiftable eccentric member can be adjusted to various positions to vary its eccentricity with respect to the axis of a driver member. The throw of the eccentric mem ber as thus adjusted, is transmitted to the welding head through a follower member and a through rock shaft which supports the welding head.

In that case, it has been necessary to loosen a bolt which holds the eccentric driver in place, rotate the eccentric member to a new position which can only be approximate, and retighten the bolt. Then the setting is checked to see if the new adjustment is proper. Since the displacement obtained by rotating an eccentric is not linearly related to the angle or degree of rotation, this is at best a cut and try arrangement which has caused loss of valuable time in the field where welds must be made expeditiously to keep up with other pipeline operations. Several settings often have been required before the proper one was obtained.

An object of the present invention is to redesign the oscillating mechanism so that it can be adjusted more accurately, more conveniently, and much quicker than the prior equipment and in a single operation, in most cases.

BRIEF DESCRIPTION OF DRAWINGS:

FIG. I is a side view of a welding carriage such as that described generally in the parent application Ser. No. 254,192 but incorporating the improved oscillating and adjusting mechanism.

FIG. 2 is an enlarged but fragmentary side view of the oscillating mechanism per se.

FIG. 3 is an enlarged sectional detail view of the eccentric driving means and associated parts, taken substantially along the line 33 of FIG. 4.

FIG. 4 is a fragmentary front view, with some parts in section and other parts omitted, taken substantially along line 44 of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT Referring first to FIG. 1, there is shown fragmentarily a section of pipe 11, as in a pipeline, on which is mounted a tensional guide band or track 13. The latter supports and guides a self-propelled welding carriage 17 which travels in an orbit around the pipeline and parallel to the joint. Flanged rollers 19 and 21 on the carriage engage the front edge of the track. Another guide roller, not shown, may engage the rear edge. A traction driving roller 22 also may engage an edge of the track to propel the carriage in its orbital path. The band or track member 13 is spaced radially away from the pipe surface by feet members 15 and is tensioned around the work by tightening means, not shown, which hold it firmly and accurately in working position. The parts so far described are substantially as in US. Pat. No. 3,604,6l2 to Nelson and Miller and form no part of the present invention. The carriage is propelled by motor means which it carries and the welding mechanism includes means for feeding electrode wire to an electric are, as well as for supplying shielding gas, etc, all as more fully described in the parent application Ser. No. 254,192, mentioned above.

Also, as described in the parent application, the carriage 17 supports a side plate or welding machine side frame 25 which is pivotally attached to the carriage by a bolt 27 at the left end of plate 25, as seen in FIG. 1. The right end of plate 25 is normally locked in working position by setting mechanism which is more fully described in the parent application, comprising precision stop means 42 and a forked member 50 which straddles a bolt 57, being secured by nut 60 and washer 59 on said bolt. By loosening appropriate parts, the carriage may be raised at its right end, swinging it pivotally about bolt 27, for cleaning, inspection, repair of burned parts, etc., as is now known in the art.

The welding head per se is shown at I61, as in the parent application, being provided with cooling fins 162 and comprising a contact tube through which the consumable electrode wire is fed to the welding are. This head is mounted to be rocked or oscillated about an axis generally perpendicular to the head, and this oscillating mechanism, and particularly the means by which it can be adjusted quickly and with precision, comprises the essence of the present invention.

A sub frame 93 secured to plate 25 comprises a pair of spaced rigid arms 77 which are pivoted on a shaft 73 mounted in ears on plate 25. This shaft, as seen in FIGS. 1 and 2, stands more or less in a vertical position, although it will be understood that this position varies because the whole apparatus swings around the pipe and other positions must be assumed from time to time. The axis 74 of shaft 73 is roughly or approximately radial to the work piece 11, although an angle of a few degrees, as shown at a is commonly provided, as explained more fully in the parent application. Sub frame 93 supports the oscillating mechanism and associated parts to be next described in a way which permits shifting it about axis 74 for aligning the welding nozzle or head with the joint on putting it precisely in the plane of the joint, whether the head is oscillating or not.

Sub frame 93 carries a bracket which extends to the right in FIGS. 1 and 2. Bracket 110 has a forward extension 112 which carries the welding head 161 at the right and is mounted through rocker arms 108 and 109 on a rocker shaft 101. The latter is supported in ears or bearings 105 and 107 formed or secured to a plate 79 which is secured to or integral with the sub frame member 93 mentioned above. With this arrangement, sub frame 93 and the parts it carries can be adjusted angularly about axis 74 to align with accuracy the welder in its proper plane. By shifting of its support means about the axis of shaft 101, the welder head also can oscillate back and forth across the weld line as it travels, while remaining in the proper weld plane in its median position.

The shaft 101 is rocked in its bearings to oscillate the welding head, that is, to reciprocate it back and forth across the weld, by the following means: An arm 114 adjustably secured to shaft 101 bears a pin 118 which projects into an opening 119 in a gyratable but nonrotatable member 130. The latter is mounted on ball bearings 132 the outer race of which press fits in a central opening of gyratable member 130. The inner race 131 of the ball bearing press fits in a recess 134 formed in a so-called eccentric member 125 which causes member 130 to gyrate. Thus, the parts 130 and 125 remain concentric with each other but the member 125 has an elongated opening 173 which engages and surrounds a bolt 128. The latter is threaded, somewhat eccentrically, into the front or right face ofa rotary driver member 122 which in turn is mounted, concentrically, on the front end of a drive shaft 98 attached through appropriate gearing to an oscillator motor 96. The motor and shaft are as described in the parent application but the member 122 is modified considerably, as will be explained. Also, the gyrating member 130 is much as in the parent application, but is modified somewhat and member 125 and the means by which it is adjusted to vary its eccentricity are quite different. Actually, member 125 is essentially circular in shape but it operates eccentrically.

Recess 134, mentioned above as being in member 125, is formed around a central projecting ring or flange 174 which extends to the right, as seen in FIG. 3, from the central part of member 125. A strong coil compression spring 170 surrounding bolt 128 bears be tween the head 171 of this bolt and a washer 172 which rests on the right or front face of the inner bearing race 131. When the parts are assembled, the force produced by spring 170 between inner race 131 and member 125 firmly holds the latter against an annular rib or thrust surface 123 of drive member 122. When member 122 is driven by motor 96, eccentric member 125 turns with it, whether the two facing parts are concentric or not. The force provided by spring 170 is sufficient under all conditions to insure that the eccentric 125 will sit firmly against member 122 which drives the oscillating.

mechanism.

When the so-called gyrating member 130 and the eccentric element 125 are set concentric with the drive shaft 98, member 130 does not gyrate or move at all, although eccentric 125 is rotating. However, if eccentric member 125 (and member 130 with it) should be shifted to a position where the eccentric 125 is not actually concentric with respect to drive shaft 98, the member 130 will gyrate but not rotate because the pin 118 in opening 119 prevents such rotation. The amplitude of gyration, and hence the amplitude of motion imparted through arm 114 to the rocker shaft 101 and carried on to the welding head, depends on the distance to which the member is moved out of concentric position with respect to shaft 98. Means for determining this distance and providing precision adjustment to obtain it will next be described.

Eccentric member 125 has a peripheral flange 190, which is of variable thickness on its rear face, and has a flange 191 on the front face which is essentially circular, annular and uniform in width. The latter surrounds and clears the rear part of the cylindrical outer surface of member 130, whereas the surface or flange 190 surrounds the essentially annular thrust surface 123 of member 122. Rim or flange 190 is semi-circular at each end but has straight or plane side sections joining the two semi-circular end portions, as shown in FIG. 4, so that it may be said to be roughly oval in shape. With its elongated central opening, member 125 can slide laterally with respect to member 122, when enough force is applied to overcome the friction imposed by spring 170. Straight or plane side portions on the generally annular thrust flange 123 on member 122 neatly fit in straight or plane parts of the essentially oval flange 190 and thus compel the member 125 to turn with driver 122. The eccentricity of member 125 with respect to member 122 and to drive shaft 98 depends, of course, on the relative positions of the two parts.

A threaded opening 181 directed radially in member 122 from its cylindrical outer surface, which member is made of a soft metal such as aluminum, is fitted with a wear-preventing coil 196 of steel wire which thus constitutes a threaded liner. Into this coil is threaded an adjusting bolt or micrometer screw 180 having a circumferential groove 187 formed in its round head which groove engages a portion 189 of flange 190 on member 125, as seen at the top of FIG. 3. The micrometer screw or bolt 180 is formed with a wrench socket 193 in its head, by means of which it can be screwed in or out of the threaded bore 181. The steel coil serving itself as both thread filler in bore 181 and as an internal thread to receive bolt 180, holds the latter firmly, thus preventing excessive rates of wear which would occur if the bolt were threaded directly into the soft aluminum member 122.

As the adjusting screw 180 is turned in or out, it moves the member 125 laterally across member 122, changing the eccentricity of member 125, and of member as well, with respect to drive shaft 98. A scale on the head of screw 180, as shown at 188, indicates accurately the adjustment being made. This scale can be calibrated to give direct measurements of the amplitude of reciprocation imparted to the welding head by the oscillating mechanism, if desired. A limit stop 184 on member 122 determines the maximum oscillation.

Zero oscillation amplitude is obtained of course when members 122 and 125 are concentric with respect to each other and to driving shaft 98.

With the arrangement just described, there is no need to loosen bolt 128 to make an adjustment. The coil spring holds the parts snugly together and prevents any play or lost motion. The groove 187 around the head of bolt closely engages the flange element 189 so that shifting of the member 125 in or out is closely and positively controlled by the screw 180, permitting a very fine adjustment. As previously indicated, this adjustment is essentially linear with respect to the angle through which screw 180 is turned, so there need be no guess work.

lt will be obvious that modifications in detail may be made without departing from the invention and it will be understood that it is intended that such modifications and variations as would occur to one skilled in the art are to be considered to be within the scope of the following Claims, as far as the state of the prior art properly permits.

What is claimed is:

1. In a welding apparatus which includes a traveling carriage adapted to move along a welding path lying substantially in a plane and a welding head moved by said carriage, the combination therewith which comprises a rockable shaft mounted in the carriage for supporting said welding head, said shaft having its axis parallel to said plane for reciprocating said head transversely with respect to said plane, an arm secured to said rockable shaft, a gyratable member positioned in the carriage to impart a rocking motion to said arm and thereby to said rockable shaft, a rotatable shaft mounted in said carriage, a laterally adjustable and rotatable eccentric member having rear and front face elements, means on said front face element for imparting gyratory motion to said gyratable member as the eccentric rotates, a driver on said rotatable shaft for engaging a driven element on said rear face of the eccentric to impart rotary motion to said eccentric, means for holding the driver resiliently and snugly against the eccentric, and means including a micrometer adjusting screw to effect lateral adjustment of said eccentric to change its position and thereby vary the throw of said eccentric.

2. Apparatus according to claim 1 in which the adjustable micrometer screw has a circumferentially grooved head engaging said eccentric to move said eecentric with precision as the screw is turned in or out.

3. Apparatus according to claim 1 in which the eccentric has a peripheral flange on its rear face defining a straight sided approximately oval area and in which a rotatable base member has on its front face a projecting thrust flange, said flange being cut away to form plane surfaces on its sides to flt neatly between the straight sides of the peripheral flange on the eccentric, thereby to positively drive the eccentric in rotation as the base member rotates.

4. Apparatus according to claim 3 in which the eccentric member is adjustable parallel to said straight or plane sides of the oval area from a position of zero eccentricity and no throw to a position of maximum eccentricity and maximum throw.

5. Apparatus according to claim 1 in which the micrometer screw is mounted in the rotatable driver and neatly engages the eccentric by means of a circumferential slot in its head to move the eccentric laterally with respect to the driver and in direct proportion to angular movement of the screw when the screw is turned in or out.

6. Apparatus according to claim 1 which includes a motor-driven rotatable driver, means for mounting the micrometer screw for radial movement in or out of said rotatable driver, and means on the head of said screw for neatly engaging the eccentric to move the eccentric laterally in the same direction that the screw moves bodily when turned.

7. Apparatus according to claim 1 in which a compression spring maintains snug contact between the eccentric and its driving means while permitting relative lateral displacement by the micrometer shifting screw. 

1. In a welding apparatus which includes a traveling carriage adapted to move along a welding path lying substantially in a pLane and a welding head moved by said carriage, the combination therewith which comprises a rockable shaft mounted in the carriage for supporting said welding head, said shaft having its axis parallel to said plane for reciprocating said head transversely with respect to said plane, an arm secured to said rockable shaft, a gyratable member positioned in the carriage to impart a rocking motion to said arm and thereby to said rockable shaft, a rotatable shaft mounted in said carriage, a laterally adjustable and rotatable eccentric member having rear and front face elements, means on said front face element for imparting gyratory motion to said gyratable member as the eccentric rotates, a driver on said rotatable shaft for engaging a driven element on said rear face of the eccentric to impart rotary motion to said eccentric, means for holding the driver resiliently and snugly against the eccentric, and means including a micrometer adjusting screw to effect lateral adjustment of said eccentric to change its position and thereby vary the throw of said eccentric.
 2. Apparatus according to claim 1 in which the adjustable micrometer screw has a circumferentially grooved head engaging said eccentric to move said eccentric with precision as the screw is turned in or out.
 3. Apparatus according to claim 1 in which the eccentric has a peripheral flange on its rear face defining a straight sided approximately oval area and in which a rotatable base member has on its front face a projecting thrust flange, said flange being cut away to form plane surfaces on its sides to fit neatly between the straight sides of the peripheral flange on the eccentric, thereby to positively drive the eccentric in rotation as the base member rotates.
 4. Apparatus according to claim 3 in which the eccentric member is adjustable parallel to said straight or plane sides of the oval area from a position of zero eccentricity and no throw to a position of maximum eccentricity and maximum throw.
 5. Apparatus according to claim 1 in which the micrometer screw is mounted in the rotatable driver and neatly engages the eccentric by means of a circumferential slot in its head to move the eccentric laterally with respect to the driver and in direct proportion to angular movement of the screw when the screw is turned in or out.
 6. Apparatus according to claim 1 which includes a motor-driven rotatable driver, means for mounting the micrometer screw for radial movement in or out of said rotatable driver, and means on the head of said screw for neatly engaging the eccentric to move the eccentric laterally in the same direction that the screw moves bodily when turned.
 7. Apparatus according to claim 1 in which a compression spring maintains snug contact between the eccentric and its driving means while permitting relative lateral displacement by the micrometer shifting screw. 